Trial Assesses 3D Stent Retriever as a Component of Penumbra's Mechanical Thrombectomy System
January 2, 2018—Raul G. Nogueira, MD, et al published results of a clinical trial evaluating the safety and efficacy of a novel three-dimensional (3D) stent retriever used in conjunction with an aspiration-based mechanical thrombectomy device (Penumbra System; Penumbra, Inc.) in terms of noninferiority to aspiration-based thrombectomy alone in acute ischemic stroke (AIS). The study is available online in the Journal of the American Medical Association (JAMA): Neurology.
As summarized in JAMA: Neurology, investigators in this randomized, noninferiority clinical trial enrolled patients at 25 North American centers from May 19, 2012 through November 19, 2015 with follow-up for 90 days. Adjudicators of the primary endpoints were masked to treatment allocation. Patients with large-vessel intracranial occlusion AIS presenting with a National Institutes of Health Stroke Scale (NIHSS) score of at least 8 within 8 hours of onset underwent 1:1 randomization to a 3D stent retriever with aspiration or aspiration alone. The primary analyses were conducted in the intention-to-treat population.
The primary effectiveness endpoint was the rate of a modified thrombolysis in cerebral infarction (mTICI) grade of 2 to 3 with a 15% noninferiority margin. Device- and procedure-related serious adverse events at 24 hours were the primary safety endpoints.
Of 8,082 patients screened, 198 patients were enrolled (111 women [56.1%] and 87 men [43.9%]; mean [standard deviation] age, 66.9  years) and randomized, including 98 patients in the 3D stent retriever with aspiration group and 100 in the aspiration alone group; an additional 238 patients were eligible but not enrolled.
The median baseline NIHSS score was 18 (interquartile range, 14–23). Eighty-two of 94 patients in the 3D stent retriever and aspiration group (87.2%) had an mTICI grade of 2 to 3 compared with 79 of 96 patients in the aspiration alone group (82.3%; difference, 4.9%; 90% confidence interval, −3.6%–13.5%). None of the other measures were significantly different between the two groups.
The investigators reported that there were device-related serious adverse events in four of 98 patients in the 3D stent retriever with aspiration group (4.1%) versus five of 100 patients in the aspiration alone group (5%); 10 of 98 patients (10.2%) versus 14 of 100 patients (14%) had procedure-related serious adverse events. A 90-day modified Rankin Scale score of 0 to 2 was reported by 39 of 86 patients in the 3D stent retriever with aspiration group (45.3%) versus 44 of 96 patients in the aspiration alone group (45.8%).
The investigators concluded that the present study provides class 1 evidence for the noninferiority of the 3D stent retriever with aspiration versus aspiration alone in AIS. Future trials should evaluate whether these results can be generalized to other stent retrievers, advised the investigators in JAMA: Neurology.